My Gym uses the handheld one in the 2nd link. It's not bad, but my understanding is that it will give you a misleading reading if you are carrying the majority of your fat somewhere that isn't between the 2 conducting points - your left and right hand. So if you have a lot of fat around your gut, but your midsection is relatively lean, it may claim you are at say 13% BF when you are really around 17+

For people that carry more weight in their legs/butt/lowerabs I think a BIA that reads from the feet may be more accurate (read: brutal)